Described herein are physically crosslinked, closed cell continuous multilayer foam structures that includes a foam layer comprising polypropylene, polyethylene, or a combination of polypropylene and polyethylene and a polyamide cap layer. The multilayer foam structure can be obtained by coextruding a multilayer structure comprising at least one foam composition layer and at least one cap composition layer, irradiating the coextruded structure with ionizing radiation, and continuously foaming the irradiated structure.

A non-woven polymeric mat for protecting pipelines, the mat including a plurality of extruded, strands derived from a polymer blend of pelletized polyvinyl chloride (PVC) resin having a k-value ranging from 60 to 70 and an olefin-based thermoplastic elastomer (TPE), wherein the amount of TPE in the polymer blend ranges from about 2.8 parts by weight to about 4 parts by weight per 100 parts by weight of PVC resin in the polymer blend and is sufficient to improve the modulus and tensile strength of the mat, and further wherein the polymer blend is devoid of a nucleating agent and is devoid of a cross-linking agent, and wherein the extruded strands have a specific gravity ranging from about 1.25 to about 1.4.

There is provided a polyolefin resin foam sheet formed by foaming a polyolefin resin, wherein the expansion ratio of the foam sheet is 1.5 to 20 cm.sup.3/g, the average cell sizes in the MD direction and the TD direction of the foam sheet are 130 μm or less, and the following formulas (1) and (2) are satisfied:
T.sub.M/D≥6  (1); and
T.sub.T/D≥5  (2), where T.sub.M denotes the tensile strength at 90° C. in the MD direction, T.sub.T denotes the tensile strength at 90° C. in the TD direction, and D denotes the density (g/cm.sup.3) of the foam sheet.

A foamed resin molded article (1) including: a foamed resin layer (30) comprising a first resin which is a copolymer including a rubber component, a vinyl cyanide monomer unit and an aromatic vinyl monomer unit, and a blowing agent; and a non-foamed resin layer (50) covering the foamed resin layer (30), wherein: the non-foamed resin layer (50) comprises a second resin which is a copolymer including a rubber component, a vinyl cyanide monomer unit, and an aromatic vinyl monomer unit; and the amount of the rubber component in the non-foamed resin layer (50), determined by pyrolysis-gas chromatography/mass spectrometry (PGC/MS), is 1% by mass or more and 30% by mass or less, based on the total mass of the second resin.

A polymer composition with increased melt strength is disclosed. The polymer composition contains at least one polypropylene polymer combined with at least one melt strength modifier. The melt strength modifier can comprise a sorbitol derivative in an amount sufficient to change the melt strength characteristics and properties of the polymer. The polymer composition can be used in thermoforming processes and to produce polymer foams. The melt strength modifier can increase the melt strength of the polymer without having to induce branching in the polypropylene polymer.

A highly fire-resistant expanded polymeric material for thermal insulation, acoustic insulation and/or fire barrier contains rubber, expandable graphite, at least one alkaline earth metal component selected from alkaline earth metal carbonates, alkaline earth metal hydroxides, hydrates of either, and combinations thereof, and a component containing silica or a silicate. The expanded polymeric material is preferably manufactured by a process including decomposition of a chemical blowing agent.

The present invention is related to a foam fabric and method of making it.

The present invention provides an electret sheet that exhibits excellent piezoelectricity even by light stress. The electret sheet of the invention is characterized by including a charged porous sheet, in which the electret sheet has a compressive elastic modulus of 80 to 300 MPa when compressively deformed at 25° C. and a 50% compression stress of 120 to 300 kPa at 25° C., and thus has the excellent piezoelectricity for light stress and exhibits the excellent piezoelectricity even by light stress (0.5 N or less) caused by a pulse wave or a breathing.

A process for producing split crosslinked polyolefin sheets comprises producing a crosslinked polyolefin foam sheet having an opposing first surface region and second surface region, and an intermediate region disposed therebetween, wherein the intermediate region is configured to have a gel content lower than an average gel content of the first surface region and the second surface region, and an average cell size larger than an average cell size of the first surface region and the second surface region; and applying a splitting force to the crosslinked foam sheet such that a controlled tear propagation travels through the intermediate region until a first side of the crosslinked polyolefin foam sheet and a second side of the crosslinked polyolefin foam sheet are separated to produce two split polyolefin foam sheets. The split crosslinked polyolefin foam sheets may comprise a skin side comprising a closed cell surface, and a split side comprising an open cell surface having peak heights of about 150 μm to about 550 μm.

A closed cell crosslinked polyolefin foam sheet comprises an opposing first surface region and second surface region, and an intermediate region disposed therebetween, wherein the intermediate region is configured to have a gel content lower than an average gel content of the first surface region and the second surface region to enable a controlled tear propagation within the intermediate region when a splitting force is applied to the closed cell crosslinked polyolefin foam sheet. For example, a ratio of a gel content of the intermediate region versus an average gel content of the first surface region and the second surface region may be about 75% or less, and a ratio of the average cell size of the intermediate region versus an average cell size of the first surface region and the second surface region may be about 125% or higher.